In the context of mailpiece delivery, a “self-mailer” is a term used to define mailpieces which employ some portion of its content information or material to form a finished mailpiece, i.e., a mailpiece ready for delivery. In addition to certain efficiencies gained from the dual use of paper stock, i.e., as both envelope and content material, self-mailers mitigate the potential for disassociation of content material from the mailing envelope, i.e., preventing mail from being delivered to an incorrect address.
One example of a self-mailer includes a sheet of content material which has been folded, e.g., a bi- or tri-fold brochure or pamphlet and sealed along a free edge such that the destination address/postage may be printed on, or applied to, a backside surface of the content material. As such, the folded sheet functions dually as both an envelope for mailing purposes and as the substrate for conveying printed content/information.
The various postal services e.g., United States Postal Service (USPS) and Royal Mail, often impose certain criteria in connection with the creation of self-mailers to ensure that the folded sheets remain secure while being handled/processed by automated postal equipment, e.g., sorters, facers, cancellers, etc. One regularly accepted and historically reliable means for securing a self-mailer include the use of adhesive tabs folded over or extending across a free edge of the folded sheets. Generally, one or two tabs are adequate to secure the folded sheets at the center, or at each end thereof, to capture the free edges.
Conventional devices or systems for creating folded self-mailers typically include a folding station, a tabbing apparatus and a conveyor/stacker. The folding station accepts one or more sheets of printed content material and folds the sheet in a bi- or tri-fold, gate-fold or Z-fold configuration. The folded sheet is then fed to the tabbing apparatus where adhesive tabs are dispensed from a carrier substrate for precise placement along at least one free edge of the folded sheet. Generally, the tabbing apparatus can be configured to perform two types of tabbing operations. In one mode of operation, the tabbing apparatus is configured to perform “edge tabbing” wherein one or more tabs are folded over an edge of the sheets, i.e., into equal halves such that half of each tab secures a folded edge of the sheet(s). In another mode of operation, the tabbing apparatus is configured to perform “surface tabbing” wherein the tab or tabs are laid flat to secure the free edge of the folded sheet(s). That is, due to the manner in which the sheets are folded, the free edge of the folded sheet(s) is not disposed along an edge of the self-mailer, but rather located at a more central location, e.g., a gate-fold. As such, the tabs are not folded over along an edge of the self-mailer, but placed and pressed flat to secure a backside surface of a folded sheet together with a free edge thereof. Whether performing edge or surface tabbing, the adhesive tab is subsequently guided into a pair of rollers where the tab is folded over the edge surfaces or pressed into engagement with the folded self-mailer. Thereafter, the finished self-mailers are fed to a conveyor/stacker and stacked for subsequent traying operations.
While these devices/systems have successfully served the needs of large volume, mail service providers, several difficulties have persisted, particularly with respect to the tabbing apparatus. For example, the rate of mailpiece creation is often limited by an inability to reliably dispense tabs as the speed of mailpiece processing equipment increases. More specifically, as speed increases, it becomes more difficult to accurately synchronize the release of each adhesive tab with a free edge of a folded sheet. Consequently, the edge or edges of each folded sheet may not be secured by equal portions of a tab. Alternatively, a tab which is inaccurately or prematurely dispensed may fall away so that the folded self-mailers are not securely tabbed.
Additionally, the carrier substrate, from which that tabs are conveyed and dispensed, can become distorted while being fed and or pulled over a “peeling blade” or “peeler bar” of the tabbing apparatus. More specifically, the carrier substrate and tabs (hereinafter referred to as the “tab stock”) are fed to the peeler bar along a first feed path, wrapped around the peeler bar to effect an abrupt change in direction, and drawn away along a second feed path by a take-away mechanism. While the abrupt change in direction dispenses the tabs from the carrier substrate, it also can impose significant torque requirements on the driving motors of the tabbing head and produce high noise levels as the tab stock distorts around the peeler bar.
Other difficulties associated tabbing apparatus relate to set-up and installation of the tab stock within the tabbing head. More specifically, set-up and installation of the tab stock can be a laborious process, i.e., consuming up to ten percent (10%) of the total labor requirements to operate the tabbing head. For example, an operator must thread the tab stock through and around a plurality of pulleys, rollers and a peeler bar. Further, the operator must remove tabs which may become dislodged during set-up or installation. Moreover, the operator must initialize the position of at least a first adhesive tab to ensure that it and subsequent tabs are properly located. With respect to the latter, an operator must painstakingly locate a first tab such that equal halves of the tab and subsequent tabs will be secured to both sides of the folded sheet material. Finally, an operator must determine/identify a target location to dispense the adhesive tabs. Generally, this is an iterative process wherein an operator (i) visually inspects the sheet material to determine the position of the free edge to be secured, and (ii) performs various manual adjustments, i.e., to the conveyor speed and tab delivery speed, to establish a suitable location for dispensing the adhesive tabs.
A need therefore exists for a tabbing apparatus which reliably and accurately dispenses adhesive tabs, is reconfigurable to facilitate installation of tab stock, and reduces the time and effort associated with the initial set-up for performing tabbing operations.